Engine.



5N0. 7|6,900. Patented Dec. 30, 1902.

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ENGINE. V

' A umio mea 1390.31 1901') (No Model.)

Witnesses QWW UNITED STATES PATENT OFFICE.

THOMAS W. JOHNSTON, OF LEROY, ILLINOIS.

ENGINE.

$PECIFICATION forming part of Letters Patent No. 716,900, dated December 30, 1902.

Application filed December 31,1901. Serial No. 87,933. (No model.)

*To all whom it may concern:

Be it known that I, THOMAS W. JOHNSTON, a citizen of the United States, residing at Leroy, in the county of McLean, State of Illinois, have invented certain new and useful Improvements in Engines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to steam-engines, and more particularly to the eccentric mechanism thereof foractuating the cut-off; and it hasfor its object to provide means for shifting the mechanism for reversing the engine which will be simple and efficient, while the strains upon the working parts are so reduced that friction is at a minimum.

A further object of the invention is to provide a mechanism that will be easy to build and which will not be liable to disorder.

Other objects and advantages of the invention will be understood from the following description.

In the drawings forming a portion of this specification, and in which like numerals of reference indicate similar parts in the several views, Figure 1 is a side elevation showing the mechanism having a valve-rod connected thereto, one of the uprights or pillow-blocks being removed and the guide-block for the cross-head being in section. Fig. 2 is a view at a right angle to Fig. 1 and showiiig both pillow-blocks and guide-block in elevation. Fig. 3 is a detail perspective view' showing the pillow-blocks, the guide-block, and the eccentric, with its strap and connect-edcross head. 7

Referring now to the drawings, there is shown the crank-shaft 5 of a steam-engine, mounted in hearings in the pillow-blocks 6 and '7, this shaft being of the usual form and having fixed thereto an eccentric-wheel 8, in the peripheral groove of which is engaged the eccentric-strap 9. The ends of the strap 9 are at the upper. side of the eccentric-wheel and extend upwardly therefrom, and between these upwardly-directed ends is engaged the lower end of the pitman 10, connected at its opposite end with the cross-head 11.

The cross-head 11 is slidably mounted in guides 12 or grooves in the inner faces of the legslS and 14 of an in verted-U-shaped guideblock 15, from the outer faces of which legs .project the trunnions 16 and 17, which are mounted in bearings at the upper ends of the pillow-blocks, as shown.

One end portion of the eccentric-strap has ears 18, between which are pivoted one end of a connecting-rod l9, pivoted at its outer end to the rocker 20, which is hung at its upper end from a pivot-pin in the upright 21. At the opposite side of the lower end of the rocker is connected a second connecting-rod 22 for connection with a valve-rod, after the manner of the ordinary eccentric-rod.

The trunnions of the guide-block are vertically above the shaft 5, and the guideways in the inner faces of the legsof the block extend both above and below the line of axis of the trunnions, beyond which the crosshead moves as the shaft rotates.

The guide-block may be tilted so that'the path of movement of the cross-head continued downwardly will lie at either side of the axis of the shaft 5, and with the crosshead at the lowerlimit of its movement if the block be shifted the cut-oif valve with which the eccentric is connected will be shifted so that the engine will be operated in a reverse direction. By referring to Fig.

l of the drawings it will be noted that if the block remain in the position shown the rocker will. be moved in one direction when the ecf the .guideblock will thus reverse the positionof the rocker at corresponding times, and the movement ofthe cut-off valve, and therewith of the engine-shaft will be reversed.

To facilitate shifting of the guide-block, a lever 25 is provided and is pivoted upon a suitable support adjacent to the notched segment 26, said lever having a pawl 27 for engagement with the segment to hold the lever in different adjusted positions. Arod 28 is connected at one end to the lever 25 and, its opposite end is bifurcated and connected.

to the legs of the guide-block.

It will be understood that in practice modifications of the specific construction shown may'be made and that when used upon a traction or similar style of engine the pillowblocks will be secured upon the boiler,while when used upon a bed-engine the blocks will be upon the bed. Furthermore, any suitable materials and proportions may be used for the various parts of the invention without departing from the spirit of the invention.

What is claimed is In an eccentric mechanism, the combination with the driving-shaft having an eccentric thereon and pillow-blocks at opposite sides of the eccentric and in which the shaft is journaled, said pillow-blocks having bearings above the shaft, of a guide-block piv- 

